Flue expander



April 4, 1939. E. w. sTEvENs FLU-E EXPANDER Filed oct. s1, 1956.

Patented Apr. 4, 1939 v 'Y UNITED STATES PATENT OFFICE' FLUE EXPAN DER Edward W. Stevens, Detroit, Mich., assigner to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Application October 31, 1936, Serial No. 108,524

6 Claims. (Cl. 15S-80.5)

This invention relates to apparatus for expand- Any suitable means may be provided for dising the end of a tube, such as a boiler flue, into tributing the live pressure fluid from the annular tight contact with a surrounding plate. chamber I I to the ends of the piston chamber a.

An object of the invention is to reduce the In the form shown, a ring valve l2 surrounds the 5 time consumed in expanding flues thereby putting end of the cylinder 5 and is arranged for radial the operation on a production basis. movement to cover alternately a port I3 leading Another object is the provision of a device to the rear end of the piston chamber and a adapted to operate in close quarters where repassage I4 leading to the front end. For a more pairs or replacements of tubes must be carried complete description of the structure and operaw out. tion of a ring valve, as shown, reference is madel A further object is to extract the expanding tool to applicants prior Patent Number 1,931,042, quickly from the tube after the latter has been granted October 1'7, 1933. Exhaust ports I5 and expanded. I6 are provided intermediate the admission ports A still further object is the provision of a tube I3 and Illa. expanding tool of small size and weight adapted The expanding tool or mandrel I8 comprises an 15 to apply maximum expanding pressure with a elongated cylindrical portion IBa having aspherihigh efficiency. cal head |817 at its front end, a collar I8c to-ward In accordance with the present invention, an the rear end and a projection I8d extending rearexpanding mandrel is driven into the end of the wardly from the collar. The collar seats against ue by a power operated hammer. After the flue the front end of an anvil block I9 which has a has been expanded, the hammer may be arrecess I9a, to receive the projection I8d on the 20 ranged to impact the mandrel in the opposite mandrel, A anged sleeve 2D, threaded onto the direction, anvil block I9 provides means for removably se- A feature of the invention resides in the concuring the mandrel I8 to the anvil block. struction of the hammer, which comprises a cyl- The anvil block assembly comprises the front 5 inder, a reciprocating piston therein, and an block I9, previously referred to, a rear anvil block anvil at each end of the cylinder, both anvils b'e- 22 and a connecting rod 23. The iront end of the ing connected tothe working tool or mandrel and connecting rod has a head 23a in the bottom of movable with respect to the cylinder. By adrecess I9a so arranged as to prevent any apprecijusting the position of the cylinder with respect able axial movement oi the connecting rod with 30 to the working tool and anvils, the piston may be respect to block I9. The rear anvil block 22 has caused to deliver either forward or rearward ima threaded connection with a connecting rod 23 pacts to the tool. and is slidably mounted in bushing 8. Rod 23 Other objects and features will appear more is surrounded by the hammer piston 6 with aclose clearly from the following description taken in sliding fit. The distance between the inner faces 30 connection with the accompanying drawing and of the iront and rear anvil blocks is somewhat 35 appended claims. Y greater than the normal travel of the piston 6.

In the accompanying drawing, The anvil block assembly I9, 23, 22 is movable Fig. 1 is a longitudinal cross section of a tube axially as a unit with respect to the cylinder 5. expander in operative relation to the work at the When the assembly is shifted to its rearmost 40 start of its operation; and position, shown in Fig. 1, the front anvil block Fig. 2 is a View, similar to Fig. 1 showingthe I9 seats against the front end of the cylinder and tube expanded and the hammer arranged to exprojects inwardly into the path of the hammer tract the mandrel from the tube. piston 6. The rear anvil block 22, in this position In the illustrative embodiment of the invention, is out of striking distance with respect to the 45 the hammer is of the uid pressure type and comhammer piston. When the anvil block assembly prises a cylinder 5 providing a piston chamber 5a is shifted forwardly, as shown in Fig. 2, the front in Which a Piston 6 recprocates. A back head 1 anvil block I9 is moved out of the path, and the has a threaded connection with the cylinder 5 rear block 22 into the path of the hammer pisand serves to clamp a bushing 8 against the rear ton. Forward movement of the assembly is limit- 50 end of the cylinder. A handle 9 is screwed to the ed by a flange 22a on the rear anvil block 22 upon back head 1. Live pressure fluid, such as comwhich is seated packing material 25 engageable pressed air, is admitted through a suitable conwith the rear end of bushing 8. nection IIJv to an annular chamber II between the It will be noted that the iront anvil block uncylinder and back head. Covers the port Ida at the extremefront end of 55 admission passage I4 when in the Fig. 2 position but covers port Illa in the Fig. 1 position. In order to provide for admission and exhaust at the front end of the piston chamber 5a at all times, a supplementary port Mb is provided.

In operation, the front end of the mandrel I8 is placed` againstthe end of a tube, such as ue F, which is to' be expanded into contact with the surrounding plate P. The cylinder 5 is pushed forward to the Fig. 1 position with the front anvil block I9 extending far into the cylinder. Live air, admitted through connection IIJ to the annular chamber II, is distributed alternately to the ends of the piston chamber under control of the ring valve I2. Assuming that the piston 6 is at the lbeginning of its rearward stroke, live air passes around the edges of the valve and underneath the same to passage Iii and port Mh tending to force the piston 6 rearwardly. The pressure on the periphery of valve i2 being balanced, the valve is held in the Fig. 1 position by the difference in pressures between passage I4 and port i3, the latter being in communication with exhaust port I5 through the rear end of the piston chamber 5a.. As soon as the piston covers exhaust port I5, it begins compressing air in the rear end 0f the piston chamber, which is in communication with the port I3. Approximately at the same time, the piston uncovers exhaust port I6 to vent the front end of the piston chamber. The increase in pressure at the rear end and the reduction in pressure at the front end of the piston chamber trip the ring valve I2 to a position in which it covers passage I4 and uncovers port I3 t0 admit live air to the rear end of the piston chamber. The rear anvil blo-ck 22 is spaced a sufficient distance from the exhaust ports I5 and I6 so that the momentum of 'the piston on` its rearward stroke is spent in compressing air in the piston chamber without lthe piston striking the anvil 22.

After the ring valve I2 has been tripped, the piston is driven forward by live air admitted through port I3, the air in front of the piston being exhausted through port IE. The covering of port I6 and uncovering of port I5 cause the valve to be tripped back to the Fig. 1 position, the operation being similar to that on the rearward stroke, excepting that the piston moves a relatively shorter distance in compressing air in front of exhaust port I6, and hence the piston strikes the front anvil block I9 with a hard blow.

The repetition of impacts delivered by the piston 6 to the front anvil block drive the expanding mandrel I3 progressively through the rtube or flue F expanding it into tight contact with the plate P as shown in Fig. 2.

To withdraw the mandrel I8 from the flue F, the operator'pulls back on the handle 9 until the parts assume the position shown in Fig. 2 in which the front anvil block I9 is spaced a greater distance from the exhaust ports I5 and It than the rear anvil block 2.2. Continued operation ofthe i piston 6 causes its forward motion to be checked by compression in the front end of the piston bodiment, it will be apparent that many changes and adaptations may be made within the spirit of the invention and Within the scope of the appended claims.

What is claimed is:

1. A fluid actuated hammer for expanding ilues and the like comprising a one-piece cylin-k der, an anvil block fitting the front end of the cylinder, an anvil block at the rear end of the cylinder, a rod connecting said front and rear anvil blocks and surrounded thereby, a percussive piston reciprocable in said cylinder, said cylinder having inlet and exhaust ports for effecting reciprocation of the piston, said blocks being spaced apart a greater distance than the length -of stroke of the piston, said piston being arranged for selectively striking either anvil block by longitudinal movement of the cylinder relative to the blocks, the front anvil block having an abutment contacting vexteriorly of the front end of the cylinder to limit forward movement of the cylinder relative to the anvil blocks and the rear anvil block having an abutment contacting exteriorly of the rear end of the cylinder to limit rearward relative movement of the cylinder.

2. A fluid actuated hammer comprising a onepiece cylinder having a bore opening at the front end of the cylinder, a front anvil block having a portion projecting into the front end of the cylinder and slidably fitting said bore, said bore providing a piston chamber whose front end is defined by said block, a piston in said chamber, means closing the rear end of said piston cham? ber, a rear anvil block at the rear end of the piston chamber, a rod connected to both blocks and projecting through the piston, said piston chamber being of uniform diameter between said anvil blocks, means including linlet and exhaust ports for effecting reciprocation of said piston, said anvil blocks being spaced apart a greater distance than the length of stroke of the piston, said cylinder being movable axially relative to said anvil blocks to adapt the piston to deliver impacts selectively in a forward or rearward direction, and means for attaching a working implement to one of the anvil blocks.

3. A tube expander comprising a rear anvil block, a front anvil lblock spaced therefrom, the front block having a recess open at its forward extremity and having a bore leadingl from said recess to its rear extremity, a connecting rod having atits front-end a head seated in the bottom of said recess, said rod projecting through said bore and being-connected at its rear end to the rear anvil block, a mandrel having a collar seated against the forward extremity of the front anvil block and having a projection in said recess positioned to restrict axial movement of the connecting rod with respect to the vfront anvil block, a sleeve 4threaded to the front anvil block and having a flange engaging the forward end ofthe collar to secure the mandrel to the front anvil block, a hammer piston slidably mounted on said connecting rod, and means for actuating said piston for delivering impacts selectively to either anvil block.

4. A fluid actuatedvhammer comprising acylinder having a bore opening at the frontend of the cylinder, a front v'anvil block having a portion projecting into the front end of the cylinder andk slidably tting said bore, said,bore provid-y ing a piston chamber whose front end is defined by said block, a piston in said chamber, means closingthe rear end of said piston chamber, a rear anvil block at the rear end of the piston chamber, a rod connected to both blocks and projecting through the piston, means including inlet and exhaust ports for leffecting reciprocation of said piston, said anvil blocks being spaced apart a greater distance than the length of stroke of the piston, said cylinder being movable axially relative to said anvil blocks to adapt the piston to deliver impacts selectively in a forward or rearward direction, and means for attaching a working implement to one of the anvil blocks, one of said inlet ports being positioned to be covered by the front anvil block when the cylinder is shifted forwardly relative to the anvil blocks and to be uncovered when the cylinder is in the opposite position.

5. A fluid actuated hammer comprising a cylinder having a bore opening at the front end of the cylinder, a front anvil block having a portion projecting into the front end of the cylinder and slidably tting said bore, said bore providing a piston chamber whose front end is dened by said block, a piston in said chamber, means closing the rear lend of said piston chamber, a rear anvil block at the rear end of the piston chamber, a rod connected to both blocks and projecting through the piston, means including inlet and exhaust ports for eecting reciprocation of said piston, said anvil blocks being spaced apart a greater distance than the length of stroke of the piston, said cylinder being movable axially relative to said anvil blocks to adapt the piston to deliver impacts selectively in a forward or rearward direction, and means for attaching a working implement to one of the anvil blocks,

the connection between the rod and rear anvil block being detachable, the rod, piston and front block being removable through the front end of the cylinder upon the disestablishment of said connection.

6. A percussive tool for expanding tubes and the like, comprising a one-piece cylinder providing a piston chamber, a back-head attached to the rear end of the cylinder, a front anvil block, a connecting rod secured to said block, a rear anvil block threadably secured to said rod, said rod being coaxial with the piston chamber, a percussive piston in said cylinder adapted to reciprocate on said rod, said blocks being spaced apart a greater distance than the range of movement of the piston, said piston being arranged for selectively striking either anvil block by movement of the cylinder relative to the anvil blocks, the iront anvil block being of the same diameter as the piston and fitting the bore of the cylinder, thereby providing a movable end wall for the piston chamber, said front anvil block having an abutment contacting the front extremity of the cylinder to limit forward movement of the cylinder relative to the anvil blocks, the rear anvil block having an abutment in back of the cylinder and backhead to limit relative rearward movement of the cylinder, said rear anvil block having an exposed portion in back of the backhead, by means of which the block may be rotated to connect or disconnect the latter with respect to said rod.

EDWARD W. STEVENS. 

